Newt Gingrich has skyrocketed to the top of the Republican field among likely Republican primary voters in South Carolina. He currently leads his closest competitor, Mitt Romney, by 19 percentage points. Romney, who vied for the lead with, then candidate, Herman Cain in October, has lost support.

Here is how the contest stands among likely Republican primary voters including those who are undecided yet leaning toward a candidate in South Carolina:

42% for Newt Gingrich

23% for Mitt Romney

9% for Ron Paul

7% for Michele Bachmann

7% for Rick Perry

3% for Jon Huntsman

2% for Rick Santorum

8% are undecided

“The road to Florida goes through South Carolina,” says Dr. Lee M. Miringoff, Director of The Marist College Institute for Public Opinion. “On the heels of Iowa and New Hampshire, South Carolina will likely again be critical for the next GOP nominee.”

What a difference two months make! In NBC News/Marist’s October survey in South Carolina, Herman Cain, who has since suspended his campaign, was neck and neck with Mitt Romney. At that time, 31% of likely Republican primary voters including those who are undecided yet leaning toward a candidate in South Carolina backed Cain while 28% were for Romney. One in ten — 10% — supported Perry, 7% rallied for Gingrich, and Paul and Bachmann each received 5%. Two percent favored Santorum while only 1% backed Huntsman. 10%, in October, were undecided.

Among the current potential Republican electorate including those who are undecided yet leaning toward a candidate, four in ten — 40% — now support Gingrich while 23% back Romney. Paul garners 9% compared with 7% for Bachmann and the same proportion — 7% — for Perry. Huntsman has the support of 3% while 2% favor Santorum. Nine percent are undecided.

Key points:

When looking at likely primary voters including those who are undecided yet leaning toward a candidate, Gingrich leads Romney by 22 percentage points among Republicans and by 14 percentage points among independents. Paul receives 6% among Republicans but 15% among independents.

Gingrich has majority support — 54% — and leads Romney — 15% — among likely Republican primary voters who are very conservative. Gingrich also has the backing of a majority — 51% — of those who support theTea Party. Among this group, Romney receives 20%.

Among those who are Evangelical Christians, 46% are for Gingrich while one in five — 20% — favors Romney.

There are gender and age differences. Although Gingrich has the lead among both men and women, nearly half of likely Republican primary voters who are men — 46% — support Gingrich compared with 38% of women. Gingrich does better among those who are older. Nearly half of likely Republican primary voters who are at least 45 years old — 49% — favor Gingrich while Romney receives the support of 23% of this group. Among those who are younger, the contest tightens. 28% support Gingrich, 22% are behind Romney, and 16% back Paul.

43% of likely Republican primary voters say they are firmly committed to their choice of candidate while 31% report they somewhat support their pick. 23% think they might vote differently. Only 3% are unsure.

When NBC News/Marist last reported this question in October, 39% of likely Republican primary voters were firmly behind their candidate. 34% were somewhat committed to their choice, and 25% said they might cast their ballot differently. Two percent, at that time, were unsure.

Key points:

Gingrich supporters are more firmly committed to their candidate than are Romney’s backers. Half of likely Republican primary voters who are behind Gingrich — 50% — report they are unwavering in their support while 34% who back Romney say the same.

Likely Republican primary voters who have a candidate preference also shared their second choice. 32% pick Romney while 21% select Gingrich. Perry is the second choice of 12% while 10% choose Bachmann. Paul garners 8% compared with 6% for Santorum. Huntsman is the second pick of 2%, and 9% are undecided.

Key points:

A majority of Romney’s supporters — 51% — pick Gingrich as their second choice while the same proportion of Gingrich’s backers — 51% — select Romney.

What if the contest for the Republican nomination comes down to Gingrich, Romney, and Paul? In that hypothetical scenario, nearly half of likely Republican primary voters — 48% — are for Gingrich compared with 30% for Romney and 12% for Paul. Nine percent are undecided.

However, if you take Paul out of the mix, nearly six in ten likely Republican primary voters in South Carolina — 57% — report they support Gingrich compared with 33% for Romney. 10% are undecided.

Now that Herman Cain is out of the Republican contest, would his endorsement make a difference? 35% of likely Republican primary voters report they are more likely to vote for a candidate who has Cain’s endorsement while 29% say they are less likely to cast their ballot for such a candidate. Three in ten — 30% — think it makes no difference to their vote, and 6% are unsure.

More than six in ten likely Republican primary voters in South Carolina — 63% — think Gingrich is a good fit for the GOP nomination. 23% agree but with reservations, and 11% believe he is unacceptable as the top of the ticket. Three percent are unsure.

Despite Romney’s challenges with the likely Republican primary electorate, a majority of these voters — 53% — say Romney is an acceptable candidate for the nomination. 31% agree but have some concerns, 14% report he is not a good fit, and 2% are unsure.

It is a different story when it comes to Paul, 34% of likely Republican primary voters say he is an unacceptable candidate for the nomination. Almost three in ten — 29% — believe he is satisfactory, and 32% find him to be acceptable but with hesitation. Five percent are unsure.

91% of likely Republican primary voters in South Carolina think it is unacceptable for a candidate to tolerate Iran building a nuclear weapon. Six percent say it is acceptable, and 3% are unsure.

When it comes to allowing illegal immigrants to obtain in-state tuition, more than eight in ten — 84% — believe it is not acceptable for a candidate to support such a position, 12% think it is acceptable, and 4% are unsure.

Many likely Republican primary voters — 62% — say it is unacceptable for a candidate to support an individual mandate for health care insurance while 29% don’t find this to be problematic. Nine percent are unsure.

Likely Republican primary voters in South Carolina divide about the acceptability of a candidate who supports amnesty for some illegal immigrants. Here, 48% find it unacceptable while 46% believe it is acceptable. Six percent are unsure.

Nearly three in ten likely Republican primary voters — 28% — say a candidate who shares their values is the most important quality for a candidate to possess. 26% want a candidate who has the same positions on the issues while 23% believe experience in a candidate is the key. 21% think it’s most important for a candidate to have the ability to defeat President Barack Obama in the general election, and 3% are unsure.

In NBC News/Marist’s October survey, values topped the list of priorities with 31%. 27% of likely Republican primary voters wanted a candidate who was closest to them on the issues while 20% said experience was the most important quality in a candidate. A similar proportion — 19% — said electability was their top priority, and 3%, at the time, were unsure.

Key points:

Gingrich does best among likely Republican primary voters who think electabilityis the key. A majority — 56% — backs Gingrich compared with 25% for Romney.

Among those who favor a candidate with experience, 43% support Gingrich while Romney receives 26%. In October, Romney was ahead among these voters. 35%, at that time, supported Romney followed by Cain with 22%. Gingrich only garnered 7% among these likely Republican primary voters.

Gingrich leads Romney by two-to-one among issues voters. 41% throw their support behind Gingrich compared with 20% for Romney

Among those who want a candidate who shares their values, Gingrich receives the support of 34% to 22% for Romney.

Many likely Republican primary voters in South Carolina describe Romney as either a liberal — 11% — or a political moderate — 51%. Only about one in four — 26% — think he is a conservative. 12% are unsure.

The problem for Romney is only 30% of likely Republican primary voters in South Carolina describe themselves as liberal or moderate, and 70% identify as conservative.

In a hypothetical general election contest between President Barack Obama and MittRomney, 45% of registered voters in South Carolina support the president while 42% back Romney, and 13% are undecided.

In NBC News/Marist’s October survey, Romney had an advantage against the president. At that time, 46% of registered voters in South Carolina supported Romney compared with 40% for Obama. 14%, at that time, were undecided.

Gingrich runs competitively against the president. Here, Obama receives 46% of the South Carolina electorate while Gingrich garners 42%. 12% of voters are undecided.

When matched against Paul, the president has a 10 percentage point lead. 47% of registered voters in South Carolina are for President Obama while 37% are for Paul. 15% are undecided.

In 2008, President Obama lost South Carolina to John McCain by nine percentage points, 45% for Obama and 54% for McCain.